News & Updates
Jan 3 2019
If you’ve ever seen a model of a small electronic train chugging along a little metal track lined with cotton-ball bushes and a painted foam mountain, you’ve seen how important scale is. In the case of a model train and its surrounding terrain, scale is important because the model visually represents an accurate depiction of what a real-life train and its surroundings would look like. Without considering scale in each of the components, the model is confusing and inaccurate.
Similarly, the idea of scaling external references, blocks, text, and the plotted drawing itself in AutoCAD is important because it impacts how things are installed and built to code in the field. If your drawings aren’t scaled properly, miscommunication and other unfavorable results occur. It’s crucial to accurately scale your drawings, especially since many of the components and systems need to go into an actual building.
Here is how you can use just some of the various AutoCAD scale commands and tools to make sure your drawings are properly communicating the visual aspects of the design.
Objects in your drawing, such as drawn lines, 3D extrusions, and more can be scaled by factors by using the SCALE command in AutoCAD itself. The objects currently in the drawing below are set at a scale of 1. However, you can change scale in AutoCAD by using the AutoCAD scale factor.
Many times, PDFs, images, and other drawing files are provided to CAD designers as something to draw on top of or use as a basis for design in AutoCAD. Through the XREF window, you may attach these items at whatever scale you choose. But what if a floor plan on an image background says that the distance between two columns is 3 ft., but it doesn’t appear to be true to dimension size once it’s inserted in your drawing?
You can use the ALIGN command to confirm dimensions on what is inserted as an external reference. See Figure 2 to see what this looks like with the steps below.
In the case of firms that may be using a lot of blocks in AutoCAD, there are ways to provide the variation of appearance with scale. Here is how you can insert blocks at different scales.
It’s important that your drawing has text that is readable, no matter what scale you are plotting to. This is where annotation becomes important. Prior to the annotative scale in AutoCAD, making your text appear the same at any given drawing scale was a challenge. You had to have multiple copies of the text at different sizes (AutoCAD scale factor) and on different layers that were only turned on when you were trying to view things at a certain drawing scale in a viewport.
Since the annotative scale concept was introduced in AutoCAD 2008, there have also been some issues. For example, when there was a disconnect between drawing scale (discussed in the next section) and the annotation object scale that would make it so text would show up at in some instances but not others.
Today, it’s much easier because you can set text and dimensions as “annotative” in the Properties Palette. This means it’ll automatically adjust to the scale you’re working with, so it appears to be the same size no matter what scale you’re at in paper space or model space. This feature, which is already available within AutoCAD, eliminates the steps of having to copy multiple sizes of text and setting them at different sizes. See Figure 5.
Fitting your drawing onto viewports in paper space is important to get the visual communication across what needs to be built and installed. If your preferred drawing scale is not available in the list, you can do the following:
When you’re drawing in model space, you draw “full size,” but to portray that in a plotted deliverable, you need to specify a plot scale as well. The plot scale lets you specify how to best portray your CAD design, given the paper size you are plotting to.
Drawing in Autocad Paper Space and Model Space
When plotting a paper space layout, you are working with two scales: the scale of the overall layout of the drawing based on paper size (usually 1:1), and the viewport scale that shows the model. The relationship between the two is that the viewport scale represents a ratio of the paper size to the size of the model within the viewports.
You could also plot from model space and treat the plot scale as the ratio of plotted units to world-size units you used to draw the model.
See Figure 7 for an example of the window itself. You’ll want to adjust it to your specific situation.
As you can see, there are many areas where AutoCAD scale can come into play. These are just some of the main features of scale that make the difference in getting your point across when your drawings are viewed in the field. More detail on these features and more is available in the help menu (F1) in AutoCAD.
Want to learn more? Watch our AutoCAD Essentials video tutorials to learn how to set up and design in AutoCAD. learn how to expertly use viewports, blocks, text and attributes, annotations, drawing templates, title blocks, and more!
About the Author
CAD Administrator and pinball enthusiast